Manufacturers of web-like textile products, such as towel, blankets and sheets, usually sew an identifying label into a hem of the product. Many manufacturers utilize automatic equipment which moves the product past a folding device and then a sewing machine to form and sew the hem. The label can be inserted manually into the folds of the hem before sewing, or one of several automatic label injecting machines can be used. In general, the problems faced when automating the label injection process include the difficulty of withdrawing one label at a time from a supply of labels, presenting the label in proper orientation to the textile product during the formation of the folds of the hem, and preventing the motion of the product from disorienting the label before it can be sewn in place.
U.S. Pat. No. 4,157l,692 discloses a label dispensing system which removes from a vertical stack contained in a housing by bowing the bottom label down to a suction head which grasps the label. Then the suction head moves in an arc lying in a plane perpendicular to the path of a towel through about 180 degrees, to a positioning suspending the label over the path of the towel. When an approaching towel is detected, a separate clamp traps the label against the towel as the suction is terminated, and the suction head returns to a position below the stack of labels.
This system requires many moving parts, first to assure that only one label is acquired by the suction head, and also because the suction cannot simply deposit the label on the towel. The transverse relative movement of the suction head could tend to catch the label on the towel, causing the label to be misaligned. Thus, the head must suspend the label above the towel. Nor can the suction head simply drop the label onto the towel, because the movement of the towel could cause misalignment. Even if the towel were stopped for placement of the label, an inefficient step leading to increased cost, the label could float out of alignment.
Other swinging suction head systems have turned the arc of the suction head into the plane parallel to the path of the towel, but many of the same problems are still encountered. In one such system, the label dispenser is slightly inclined to the horizontal, and the suction head is operated to move into the magazine to engage the next label, pull it out of the magazine, and swing it down to the path of the towel. The label passes through a slot in the hemming track that folds the edge of the towel in a hem. This system requires complex control apparatus to precisely time the movement of the suction head.
Another automatic label handling system is disclosed in U.S. Pat. No. 4,505,467, according to which a suction head pulls a label off the bottom of an inclined dispenser holding a plurality of labels. A fork moving in the plane of the label then pushes the label off the suction head, after which it drops into an inclined chute where it is trapped by belts and fed down onto the towel. Another belt picks up the label in a conventional manner and holds it on the towel along the path to the sewing needle. It may be seen that this device depends upon the fork sliding the label off the suction head without folding or buckling the label, and releasing the label to let it free fall into the chute, all without changing the orientation of the label. Again, a relatively large number of moving parts is required, and it appears they must be carefully aligned to result in the label reaching the towel in proper alignment with the hem. IN practice, problems have arisen with one version of this system in which the belts in the chute were driven by the movement of the towel. The belts in the chute tended to lose synchronization of speed and to turn the labels travelling down to the towel.
Other label handling systems are shown in U.S. Pat. Nos. 4,305,338; 4,590,872; and 4,682,446. These systems position labels for sewing, but do not relate to inserting labels in hems.
Thus, there has long been a need in the art for a label injector capable of selecting a single label from a supply of labels and placing the label with consistent accuracy into the hem of a moving towel or other textile item, without slowing down the production rate of towels being hemmed. There has also been a need for such a label injector which has few moving parts, and can easily be moved away from the path of the towels to permit access to the injector and to other parts for maintenance.